The present invention relates generally to glow plugs for engines and, more particularly, to an ion sensor glow plug assembly for an engine of a vehicle.
It is known to provide an ion sensor for an engine of a vehicle. The ion sensor is used as a closed loop feedback to detect fuel injection timing and intensity of combustion in each cylinder of the engine so as to control and improve engine performance.
It is also known to provide a glow plug for a compression ignition engine such as a diesel engine. The glow plug typically has a metal glow tip that extends into a chamber of the engine. The purpose of the glow plug is to aid in cold starting of the diesel engine.
Although the above ion sensors and glow plugs have worked, it is desirable to combine the two to provide an ion sensor glow plug assembly. It is also desirable to provide an ion sensor glow plug assembly that is self-cleaning for soot in a compression ignition engine such as a diesel engine of a vehicle.
It is, therefore, one object of the present invention to provide an ion sensor glow plug assembly for an engine of a vehicle.
It is another object of the present invention to provide an ion sensor glow plug assembly that is self-cleaning for soot in a compression ignition engine of a vehicle.
To achieve the foregoing objects, the present invention is an ion sensor glow plug assembly including a metal shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes a center terminal disposed at least partially in the passageway of the shell and connected to a source of power to create a heating circuit. The ion sensor glow plug assembly includes a glow sheath disposed at least partially in the passageway of the shell and about the center terminal to create an ion sensing circuit. The ion sensor glow plug assembly further includes a coating disposed about a portion of the glow sheath between the glow sheath and the shell to isolate the shell from the glow sheath and extending axially into a glow area of the glow sheath to clean off soot on the glow sheath by glowing.
One advantage of the present invention is that an ion sensor glow plug assembly is provided for an engine of a vehicle. Another advantage of the present invention is that the ion sensor glow plug assembly is self-cleaning for soot in a compression ignition engine such as a diesel engine. Yet another advantage of the present invention is that the ion sensor glow plug assembly incorporates a metal glow sheath with a ceramic barrier coating deposited on it to isolate it from a steel shell for ion sensing purposes. A further advantage of the present invention is that the ion sensor glow plug assembly allows closed loop control of a compression ignition engine such as a diesel engine.
Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.